and what will it provide for us in the future? narrator: to understand the statof the oceans today, jackson uses data from fish surveys conducted worldwide, along with catch records from the fishing industry. but this data does not provide him with all the answers he's looking for. dr. jackson: if you wanted to know what manhattan island was like as a natural ecosystem, you wouldn't go to wall street and survey the birds. wall street has changed in the last 500 years. and in the same kind of way, if you want to know what kind of fish there were in the ocean, you can do a scientific survey of fish today, but it wouldn't tell you anything. some species of fish are extinct, so it would probably be difficult to survey them. narrator: so to put current research in the right context, jackson compares it with historical records and archeological evidence, painting as accurate a picture as possible of the oceans before human disturbance. this picture is called a baseline. dr. jackson: the baseline is the way it used to be. but every gener